1. Field of Invention
Since the advent of horse drawn wagons, such vehicles have been used to transport cargo too bulky or too heavy to be carried by hand, wheel barrows or the like.
If the cargo to be transported was too heavy and it could not be hoisted to the bed of the wagon, the options were to use a ramp, or the wagon could be backed up to an elevated platform, known in more modern day parlance as a loading dock.
When wagons got motors and became trucks, they were faster, and more efficient, but loading and unloading cargo remained a problem.
Probably the next step in the evolution of the process of heavy cargo on and off loading, is the venerable fork lift. However, fork lifts can be dangerous and cumbersome in limited space and, of course, availability is a perpetual problem. A better system was needed.
Since loading docks and fork lifts, are not always available where needed, the lift gate was developed and mounted to the rear of the transport vehicle so that cargo could be loaded or unloaded no matter where the vehicle was located. However, lift gates are limited in size and capacity and, therefore, limited as to their usefulness.
The present invention seeks to obviate the several problems inherent in the loading and unloading of cargo through the ingenious process of bringing the vehicle to the cargo, rather than the cargo to the vehicle, as will become more clear hereinafter.
2. Description of prior Art
Previous paragraphs track a part of the evolution in loading and unloading practices which constitute, for the most part, the significant prior art. Nonetheless, the search continues to find a safe and efficient means of loading and unloading heavy, and/or bulky cargo, and it is generally accepted that the safest and most efficient way of accomplishing the desired result is not to have to lift or elevate the cargo onto the bed of the vehicle.
With this in mind, innovators such as Ives and Foster conceived the idea of tilting the bed of the vehicle, and they obtained U.S. Pat. Nos. 2,462,868 and 2,487,325, respectively, as a reward for their efforts.
In the '50's, air bags became the subject of considerable research and development, although primarily as a substitute for, or adjunct with, steel springs in a vehicle suspension. Seale, in his U.S. Pat. No. 2,784,978, envisioned the possibility of using air bags to level loads, or otherwise compensate for uneven load distribution.
In the early '70's, Pulgliese, in his U.S. Pat. No. 3,633,775, recognized the potential of air bags in lowering one end of the bed of a truck to make it easier to load cargo thereon, and Evans offered a variation on that theme by patenting his boat trailer [2,957,593]. These early efforts, however, were directed toward solving highly specialized problems and do not address the needs of the over the road cargo hauling industry . . . enter the present invention.
The cargo transportation industry, from recreational to industrial use, has been supplied by the motor vehicle manufacturing companies and trailer manufacturing companies with suspensions that attempt to hold the "bed" at a calibrated height up to the maximum weight capacities.
Originally, leaf-type springs were utilized to "soften" the ride, however, with little or no cargo the ride was quite jolting. Thereafter, inventors created several types of suspensions to create a softer ride by including a coil spring, and/or "shock absorber", air assisted "shocks", torsion bar suspension, air bag suspension system with a leveling valve. All of these "systems" were designed to "carry" the load, with some attempted driver and passenger comfort.
Another dilemma the transportation industry faced was the loading and unloading of cargo. At warehouses and large stores, "docks" were built to the height of the "bed" for easy removal and loading of box cars, trucks, and trailers. This was fine if the final destination was at another "dock", but generally the final destination was ground level and various inventions, such as the hydraulic tailgate, (a tailgate made in such a fashion as to become horizontal then lower hydraulically to ground level with or without a load and then return. This had to be operated with at least one hand while the other hand had to balance the load. It had the potential of being very hazardous and time-consuming.
Another was a "bed" that could be hydraulically moved in such a way as to have: a loading angle of 9 degrees to 20 degrees. Again, the problem was loading and unloading without damage to the cargo and immobilizing the cargo (tying down, securing). Another method was where the "bed" was hydraulically unloaded from the frame of the "chassis".
All of these methods had problems, such as inefficiency in time management, potential hazards to the operator in loading or unloading, and because of heavy suspension needed for the load when the vehicle was empty, the ride became harder and caused back injuries to the operator. Bigger or higher vehicles had to be made to handle the heavier loads and getting up and down from these vehicles made knees wear out before their time. Falling accidents also occurred more frequently.
Low-height "beds" were more efficient but ramps still had to be used and more space was required. Livestock balked at going up any type of ramp. Heavy springs caused laws to be passed in most states requiring the exercising of race horses every three to four hours of traveling because of possible hazards to their knee joints. Bed heights 40" and higher are dangerous because of the high center of gravity causing "tip overs" and "jack-knifing". Wind resistance is greater making it less economical.
The conventional "slide back" car carrier has become obsolete because of its high load angle. Auto manufacturers are "lowering" their cars, making them more aerodynamic, more efficient, etc. Because of the new four-wheel drive and four-wheel steering cars, tow trucks with wheel lift capabilities are not able to retrieve them economically either.
All the previous cargo vehicle designs heretofore known suffer from a variety of disadvantages, among them:
1. They are not for operator and/or passenger comfort and safety. PA1 2. Fixed "bed" height, such that awkward and dangerous loading and unloading procedures are required. PA1 3. Higher center of gravity subject to "tip over", "jack-knifing", etc. PA1 4. Dock and ground level loading and unloading problems. PA1 5. Roll back--slide back type car carriers have excessive load angles. PA1 6. Excessive time required to prepare for loading or unloading and securing load.